Easy open containers have found widespread acceptance and extensive use in various applications. Perhaps the best-known such application is in the field of beverage containers, where individual cans of beverages such as beer or soft drinks are equipped with an end wall having a manually-openable structure.
In recent years, easy-open ends intended for beverage containers have included nondetachable tabs or related elements which remained with the can after opening, for ecological reasons. Although various easy-open can ends have become known to the art, these ends generally have in common the traditional function of selectably providing a relatively small opening in the end wall of a can or other container, so that the contents of the container can be drunk or otherwise dispensed through the opening. This opening typically is formed in the can and by tearing away or otherwise detaching a removable panel from the end wall. Once this panel is detached, the container is opened and cannot be closed thereafter to protect or preserve its contents. While this presents no problem if the entire contents of the container are consumed immediately after opening, many persons find their appetites satisfied after drinking only part of a newly-opened beverage, or for some other reason desire to set aside the beverage for later consumption or use.
A partially-empty beverage container needs to be reclosed in some fashion when saving the contents for later. Reclosing the container prevents or at least retards spoilage, and prevents contamination from foreign objects entering the opened container. Even where the opened container is stored in a refrigerator or other enclosure, reclosing the container helps prevent a stale taste due to commingling of odors with other foods in the refrigerator, or due to decomposition from exposure with air. Moreover, an airtight reclosure helps maintain carbonation of carbonated beverages such as soft drinks or beer.
While container reclosure may be relatively straightforward with bottles using screw-on caps, reclosing the typical beverage can is another matter. The tear-out panel associated with the typical easy-open can generally is deformed and/or positioned within the can below the end wall during the opening procedure, and thus is unavailable to reclose the opening in that wall. Prior-art expedients to overcome this problem generally have utilized separate stoppers , purchased as accessories, intended to fit on the end of an opened can and temporarily plug the opening. These separate stoppers are relatively small and easily misplaced or simply forgotten, and thus are usually unavailable to someone wanting to reclose an open beverage container. Furthermore, the structural variations between easy-open ends supplied by different manufacturers makes it difficult to provide an accessory stopper which effectively works with the variety of beverage cans commonly available to consumers.
Prior-art attempts to incorporate a reclosure on the structure of a beverage can generally have not met with acceptance in the can industry. One example of a prior art reclosure is shown in U.S. Pat. No. 3,880,319.